Variability in Zataria multiflora Bioss. essential oil of twelve populations from Fars province, Iran

• Comparison of different Zataria multiflora ecotypes growing in different parts of Iran.
• Various genetic and environmental factors could influence the essential oil compounds.
• Three chemotypes for this species have been recognized.
• Chemotypes are carvacrol, linalool and thymol.

Zatariamultiflora is a traditional and popular spice in Iran. The aerial parts, including flowers, were collected from 12 Z. multiflora plant populations (Zarghan, Khonj, Sivand (1–4), Marvdasht (1–4), Firoozabad, and Chahakneyriz) growing in Fars province, located in southwestern Iran. The essential oils were obtained by hydro-distillation using a Clevenger-type apparatus and were analysed for semi-quantitative and qualitative variations in essential oils. The essential oil yields were measured on the basis of the volume of dried essential oil/primary dried material weight × 100 for each sample. The essential oil yields ranged from 2.91% to 4% (w/w). Analysis of variance showed that geographic variation had a significant effect on the oil content in plants of different regions. A maximum difference of 1.09% (w/w) was observed between the Sivand 3 and Zarghan populations. Three ecotypes, Zarghan, Marvdasht 3, and Marvdasht 4, possessed the maximum essential oil yield. Fifty volatile compounds were identified by GC and GC–MS analysis. The main essential oil components were linalool (0.93–55.69%), thymol (2.66–37.51%), carvacrol (14.37–59.78%), γ-terpinene (2.28–11.35%), ρ-cymene (1.23–7.9%), carvacrol methyl ether (0.9–6.08%), α-pinene (1.3–5.13%), and myrcene (0.51–2.72%). Analysis of the principal components based on the mean relative amounts of essential oil components led to the identification of three chemotypes: carvacrol, thymol, and linalool of which the thymol chemotype is found more frequently in different parts of Iran. The chemical variability could be attributed to genetic and environmental factors. The characterization of essential oil variation is of commercial importance as well as being helpful in the improvement of Z. multiflora resources for pharmaceutical and food industries.